非规则甲板板架稳定性计算方法研究

研究表明,应用有限元程序计算非规则甲板板架的稳定性符合实船的结构承载状态,它比常规的甲板稳定性计算方法更精确,更合理,并指出,目前实船上采用的甲板板架布置可进一步改进,使纵桁,纵骨和横梁的布置更加合理,在确保甲板板架稳定性满足规范要求的基础上减轻结构的重量。     

多跨失稳的船体梁极限强度的Smith法修正研究

为了考虑多跨失稳对船体梁极限强度的影响和拓宽Smith法的适用范围,分别对两端弹性支持的横梁和一端弹性固定横梁支撑的纵骨,提出多跨失稳的纵骨梁柱屈曲载荷-端缩曲线的计算方法,并推导了相应的公式。采用多跨失稳理论和非线性有限元法,进行大跨度甲板板架的极限强度计算,分析纵骨截面惯性矩、纵骨间距、横梁间距、横梁跨距、横梁截面惯性矩、横梁数目、纵桁长度和扇形惯性矩等因素对纵骨多跨失稳极限载荷的影响。应用论文建议的公式和非线性有限元方法,对一艘115000 DWT单舷侧散货船进行了触底和碰撞破损后考虑多跨失稳的船体梁极限强度计算和相互比较。计算结果表明,论文建议的方法具有较高的精度。     

大跨度加筋板架优化设计研究

在大跨度双层甲板设计中,横向舱壁起到了代替强横梁支撑甲板板架的作用,相比于单层甲板设计可以减小主要构件的腹板高度。本文将横向舱壁简化为两端简支的大跨度加筋板架,使用有限元方法研究其在均布载荷作用下的响应。分析了板厚、扶强材尺寸和间距对结构强度和稳定性的影响,并讨论了以结构重量最小为目标的优化设计方法。     

基于舱段模型的大开口甲板结构稳定性分析与设计

针对某大开口舱段结构,采用有限元方法（FEM）对比分析3种计算模型位移载荷作用下第1层甲板纵骨轴向应力的分布.计算结果表明,该应力分布存在较大程度的不均匀性,采用双层板架模型或立体舱段模型能获得较准确的纵骨轴向应力分布.同时,分析2种基于稳定性要求的大开口甲板纵骨设计理念的优劣.为合理利用结构材料,均衡各区域纵骨的稳定性储备,建议在设计甲板纵骨时要考虑大开口甲板纵骨轴向应力分布的不均匀性.     

焊接变形和应力对甲板板架极限强度的影响

船舶建造过程中,焊接引起的结构变形和应力对船舶结构性能产生影响。以典型船舶甲板板架为例,研究焊接初始缺陷对甲板板架极限强度的影响。采用数值仿真方法模拟甲板板架的焊接过程,获得结构焊接变形和残余应力,对含初始缺陷的板架结构施加轴向压缩载荷,计算板架结构的极限强度,并与理想结构进行比较研究。结果表明,轴向压缩载荷下,甲板板变形过大是引起板架整体失稳的主要因素;焊接变形及残余应力显著地削弱甲板板架极限承载能力,焊接初始缺陷降低甲板板架整体刚度,影响结构失效模式。     

国内船舶结构稳定性研究进展

综述了国内船舶结构稳定性研究现状.根据结构形式的不同,分别介绍了板格和加筋板以及板架稳定性研究成果;根据中垂时甲板板架所受压应力最大,介绍了甲板板架的稳定性研究成果;根据结构形式的特殊性,介绍了双层板架和大开口板架的稳定性研究成果;并对稳定性的可靠性分析和方法论方面的研究成果做了简单介绍.指出对大跨度、大开口、双层板架的稳定性问题需要进一步开展研究.     

用ANSYS进行甲板板架稳定性计算

研究了用ANSYS软件进行线弹性甲板板架稳定性计算的实用方法。介绍了采用ANSYS进行结构稳定性计算的理论及结构失稳计算的一般步骤，用支柱稳定性计算和板稳定性算例验证了ANSYS线弹性结构失稳计算的正确性，以此为基础研究了用ANSYS对甲板板架失稳的计算方法。通过对未简化和简化的两种甲板板架有限元模型的计算，表明采用简化的板架有限元模型可方便获得甲板板架结构的整体欧拉应力值。     

水面舰船规范中甲板纵骨稳定性校核的差异研究

甲板纵骨的稳定性问题是水面舰船结构设计中的一个重要问题。《舰船通用规范》和《水面舰艇结构设计计算方法》对纵骨带板折减系数取法的差异有时会导致工程中出现不同的结果。从理论上分析了《舰船通用规范》和《水面舰艇结构设计计算方法》对纵骨屈曲分析评估方法的差异,并用数值算例结果给予说明。研究结果为:《舰船通用规范》中的稳定性校核标准较《水面舰艇结构设计计算方法》严格,对于理解和修订国军标以及保证舰船结构安全有一定的理论意义和实用价值。     

横骨架式甲板板在丧失稳定以后的工作性能

本文主要讨论了考虑横梁抗扭刚度对甲板板在丧失稳定性以后的工作性能的影响。文中应用布勃诺夫-迦辽金法求解了V.卡门(Karman)微分方程组。从而导得了考虑横梁抗扭刚度对板的减缩系数φ的近似计算公式,并对当前船用的横梁可能尺度和型式进行了数值计算,列成了表格和曲线。计算结果表明:对于横骨架式船舶甲板板失稳后的减缩系数在边长比大于2时采用索柯洛夫解是适宜的。但是在边长比小于2时,计及横梁的抗扭刚度对甲板板的稳定性及失稳后的工作性能起有利的影响。这种影响随型钢尺寸的增大而增加,随比值λ=a/b的增加而减小。此时索柯洛夫的解给出了过低的减缩系数值。计算结果还发现当λ大于2时,进行多次近似计算是必要的。而对于正方形板,一次近似计算是足够精确的。在这些论点的基础上,本文最后对正方形板计及横梁的弹性固定作用时在失稳后的减缩系数建议采用计算公式φ=0.53 0.47(1/n)。     

计及侧向载荷作用的纵骨梁柱多跨失稳载荷-端缩曲线确定方法

针对现有船体梁极限承载能力计算的Smith法不能计及侧向载荷作用的问题,本文提出了一种考虑侧向载荷作用下板架变形的纵骨梁柱失稳的屈曲载荷计算模型和方法,推导了计及侧向压力对板架影响的纵骨梁柱屈曲载荷-端缩曲线公式。进行了纵向与侧向载荷共同作用下三个板架的极限承载力计算,分析讨论了侧向载荷、板架参数等对纵骨梁柱屈曲极限强度的影响规律。应用本文方法编制了考虑侧向荷载作用的船体梁极限强度程序,进行了实船的计算和对比分析。     

A comparative study on the hull strength of a ship with thin-walled box girders

1 Introduction1 The permanent aim is that the ship designers try to optimize the ship structure to improve the strength of hull. The traditional design of ship structure avoiding damage is involved with many transverse bulkheads set up in the ship in orde…     

桁材开孔腹板的线性屈曲强度分析

船体在总纵弯曲时甲板纵桁和船底纵桁承受较大的轴向压力,而在桁材腹板上开孔会影响其腹板的屈曲强度.针对这一问题,应用有限元屈曲特征值分析方法对受轴向压力开孔腹板的屈曲载荷进行计算.通过对计算结果的分析,对开孔尺寸和开孔位置对腹板屈曲强度影响的规律进行了归纳,并对腰圆孔和圆孔对腹板屈曲的影响程度做出了比较,对船体结构中腹板开孔尺寸及位置提出了一些建议.     

Research on the dynamic buckling of a typical deck grillage structure subjected to in-plane impact Load

The dynamic buckling of the main deck grillage would result in the total collapse of the ship hull subjected to a far-filed underwater explosion. This dynamic buckling is mainly due to the dynamic moment of the ship hull when the ship hull experiences a sudden movement under impact load from the explosion. In order to investigate the ultimate strength of a typical deck grillage under quasi-static and dynamic in-plane compressive load, a structure model, in which the real constrained condition of the deck grillage was taken into consideration, was designed and manufactured. The quasi-static ultimate strength and damage mode of the deck grillage under in-plane compressive load was experimentally investigated. The Finite Element Method (FEM) was employed to predict the ultimate strength of the deck grillage subjected to quasi-static in-plane compressive load, and was validated by comparing the results from experimental tests and numerical simulations. In addition, the numerical simulations of dynamic buckling of the same model under in-plane impact load was performed, in which the influences of the load amplitude and the frequency of dynamic impact load, as well as the initial stress and deflection induced by wave load on the ultimate strength and failure mode were investigated. The results show that the dynamic buckling mode is quite different from the failure mode of the structure subjected to quasi-static in-plane compressive load. The displacements of deck edge in the vertical direction and the axial displacements are getting larger with the decrease of impact frequency. Besides, it is found that the dynamic buckling strength roughly linearly decreased with the increase of initial proportion of the static ultimate strength P₀. The conclusions drawn from the researches of this paper would help better designing of the ship structure under impact loads.     

Experimental and numerical investigations of the ultimate torsional strength of an ultra large container ship

Structures of ultra large container ships (ULCS) are characterized by large deck openings and low torsional rigidity. It is essential to comprehensively figure out their collapse behaviors under pure torsion with both model experiments and numerical simulations, making an evaluation of their ultimate torsional strength. In this paper, a similar scale model of a 10,000TEU container ship has been designed and manufactured first, in which both geometric similarity and strength similarity are taken into account. Next the collapse behaviors of the test model are detailedly illustrated with both experimentally and numerically obtained results. Then discussions on warping or shear buckling deformations involved in the collapse process of the structure are conducted with extended numerical simulations. Finally, the ultimate torsional strength of the true ship is evaluated according to the similarity theory. Results show that it is the yielding and shear buckling of the side shells that causes the failure of the hull girder under pure torsion. Further nonlinear finite element analysis demonstrates that it may either have warping or shear buckling deformations in the torsional collapse process of the hull girder with a large deck opening, depending on the local rigidity distribution of side shells, which has a significant effect on the ultimate torsional strength of the hull girder.     

基于LR规范的豪华邮轮全船有限元分析流程及应用

对豪华邮轮进行全船结构强度分析是其结构设计的必要条件。文章基于LR规范,介绍豪华邮轮有限元分析流程,包括边界条件、设计载荷、计算工况和强度准则等,以某艘14万总吨级的豪华邮轮为实例,采用有限元手段对其全船结构强度进行计算,并分析应力分布特点和主要纵向连续结构的有效度,结果表明:该邮轮结构的总纵正应力和剪应力主要分别由甲板结构及连续纵舱壁结构参与传递。该结论可为豪华邮轮结构设计提供一些参考。     

两种强力甲板结构形式在大变形损伤状态下的极限强度分析

针对2种不同强力甲板结构形式的舰船,应用ABAQUS非线性有限元分析工具,计算舰体在强力甲板大变形损伤状态下的总纵极限承载能力.采用冲击动载荷来模拟得到结构的大变形损伤状态,并将其作为初始状态进行极限承载能力分析.分析结果表明,纵向箱形梁这种新型强力甲板结构形式相比常规强力甲板结构形式,在大变形损伤下舰体总纵极限承载能力等方面具有显著的优越性.     

Analysis of the accident of the MVNakhodka. Part 2. Estimation of structural strength

In the early morning of January 2, 1997, a Russian tanker, the MVNakhodka, broke in two in the Sea of Japan. The fore part of the vessel drifted and was stranded on the coast of Japan, and the aft part sank. The coast of Japan was seriously polluted by spilled heavy oil. Following this disaster, the Japanese Government established a Committee for the Investigation of the Causes of the Casualty of theNakhodka. This paper deals with the structural strength of MVNakhodka at the time of the accident. First the structural characteristics of theNakhodka are described, and the reduction in thickness of the structural members are estimated based on the data measured on the fore part of the vessel which drifted ashose. Then the ultimate longitudinal strength of the hull girder at the time of the accident is evaluated by applying Smith's method, and the possibility of break-up collapse due to excess loads is discussed. The mechanism of fracture at the bottom plate is also discussed based on the observed fracture surfuce of the cross section. Finally an FEM (finite element method) simulation of the break-up of the hull girder is performed. It is shown that buckling/plastic collapse took place at the deck plate near Fr.153, which was followed by the successive buckling collapse of the side shell plate of the hull girder. Right after the collapse of the deck structure, the bottom plate fractured just in front of the transverse bulkhead at Fr.153. This article is based on an article that appeared in Japanese in the Journal of the Society of Naval Architects of Japan, vol. 183 (1998).     

甲板运输船艏部舱段有限元强度分析

考虑甲板运输船的甲板相对较宽,容易导致尺度比超出规范的限定,因此其强度分析应该特殊考虑.利用有限元分析软件MSC.Patran/Nastran建立舱段有限元模型,对甲板运输船的艏部舱段在总纵外载荷、外部水压力和甲板局部载荷作用下的强度进行直接计算和分析.     

接触爆炸下舰船强力甲板塑性动态响应特性研究

基于舰船强力甲板结构和接触爆炸工况设计,采用非线性有限元计算方法对在不同炸药量下、不同尺寸的纵桁和强横梁的强力甲板进行接触爆炸数值模拟。分析球形炸药接触爆炸下空气冲击波的压力分布以及对甲板的冲击过程,结果显示强力甲板结构在接触爆炸下呈现出3种破坏模式,并通过定义构件相对强度因子,提出了破坏模式的判别条件,初步揭示舰船强力甲板在接触爆炸下的塑性动态响应特性。     

UR-S11A对大型集装箱船结构设计的影响研究

国际船级社协会针对集装箱船的新标准UR-S11A已于2016年7月1日正式生效,其对大型集装箱船结构设计的具体影响值得研究。以一艘13 500 TEU集装箱船为例,首先分析了UR-S11A相比UR-S11和劳氏船级社(LR)规范在强度校核上的差异,然后通过对总纵屈服强度、屈曲强度和极限强度的研究分析了新标准对船体结构的影响。结果表明,UR-S11A对在0.3~0.4船长处船体梁的总纵弯曲和极限强度的要求更高,部分纵舱壁板与外板的剪切和屈曲强度以及双层底桁材纵骨的屈曲强度受新规范影响较大。